The present invention relates to the field of systems and apparatus for facilitating manual and/or mechanized work operations (e.g., assembly operations) on a work piece or product supported on a carrier and, more specifically, to a universal low cost, standardized modular unit which is usable alone for effecting performance of selected work operations or, alternatively, is usable in combination with one or more similar units to form an inline production line.
Contemporary production or assembly line techniques for economically mass producing products find their roots in the automobile industry as a result of Henry Ford's "better idea" during the early part of the century.
His idea was simple enough. Progressively advance the product to a series of work stations where components are added in sequence until the assembly is complete.
Over the years, his basic concept has been developed in a number of different ways. In some production lines, the product is supported on a carrier which is transported by a conveyor at a fixed rate along the line thereby requiring the performance of work operations, whether manual or mechanized, to be "synchronized" with the rate of conveyor movement. In other production lines, the carrier is removed from the conveyor at each work station allowing work operations to be performed in a nonsynchronous manner.
The synchronous system works best when the product and its associated assembly operations are relatively simple. However, for a mechanically complex product the nonsynchronized system is preferred because it allows a worker or automatic assembly machine to work at their own optimized rate independent of the rate of conveyor movement. This type of system also provides a great deal of flexibility by allowing an optimized mix of manual and mechanized work stations on the same line and facilitates a subsequent changeover at selected work stations from manual to mechanized assembly in the interests of reducing labor costs or increasing the production volume of a given line.
Generally, production lines are specifically designed for, and "dedicated" to, the assembly of a given product. That is, the product is analyzed for required work operations; production volume and space requirements are considered; and then a dedicated work piece carrier and conveyor-connected work stations are designed. In many instances, a pilot line is built first to test the design of the equipment before the scaled up full production line is assembled.
Obviously, for such a "dedicated" production line to be cost effective, the specific product must be manufactured in large volumes over a specified length of time to recapture the initial costs of building the line. If for some reason the product is taken out of production earlier than planned, or is changed radically so that it no longer can be built on the dedicated production line, at least a portion of the initial investment is lost. Many times, the dedicated nature of the carrier, conveyor system and work stations precludes the reuse of this equipment in a subsequent production line for a follow-up product thereby increasing the economic loss.
There have been some attempts at building a production line with reusable modular units. One such system, known as the Lanco Economic, manufactured by Lanco (Langendorf Watch Co. of Switzerland) utilizes a modular unit in which 25, 50 or 100 dedicated carriers are attached to an endless horizontal chain conveyor for sequential presentation at a work position at the front of the unit. The operator controls the chain drive and may work at his or her own rate. Alternatively, the unit may be used in conjunction with an automatic assembly machine for performing the selected work operation. After completion of work on all of the piece parts in the unit, it is manually moved (on integral bottom rollers) along a work table to the next assembly station. In addition to lacking provisions for automatically transporting the carriers to sequential assembly stations, the entire dedicated carrier must be discarded and replaced with a new dedicated carrier to manufacture a follow on product.
Therefore, it is a primary object of the present invention to provide an economical system for facilitating manual and/or mechanized work operations on a product where its major modular components need not be dedicated to the production of a particular product, but rather may be reused in a variety of arrangements to create production lines for different products.
It is yet another object to provide such a system that is flexible and allows a production line to be varied to accommodate changing production requirements or a change in product design.
Another object is to provide such a system which uses relatively inexpensive universal standardized modular units in combination to form a production line.
Yet another object is to provide such a system wherein essential functions common to a variety of different production lines, such as carrier transport and automatic location of a carrier at a fixed work position with a work station are incorporated into interchangeable reusable modular units.
Another object is to provide such an economical system that is configured for substantially nonsynchronous work operations.
Yet another object is to provide such a system that allows productions on carriers to be accumulated at various points along a production line formed by two or more of such standardized modular units.
Still another object is to provide a product carrier that is only partially dedicated to a particular product so that the most expensive portion of the carrier may be reused for the manufacture of a different or redesigned product.
Another object is to provide such a system that allows an optimized mix of manual and mechanized work operations on the same production line.
Yet another object is to provide such a system that allows the conversion of a manual work station to a mechanized work station, or vica-versa, at minimum expense with little disruption in production flow.
Another object is to provide such a system wherein the production line is formed by modular units which may be easily interchanged in the event a unit fails and needs to be repaired.
Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.